Transmission device, transmission method, reception device, and reception method

ABSTRACT

The transmission device generates a physical layer frame having preambles and a payload that includes, in the preamble, time information representing time of a given position in a stream of physical layer frames and transmits the physical layer frame. The reception device receives the physical layer frame and performs processes using time information. The present technology is applicable, for example, to IP packet broadcasting.

TECHNICAL FIELD

The present technology relates to a transmission device, a transmissionmethod, a reception device, and a reception method, and relatesparticularly to a transmission device, a transmission method, areception device, and a reception method that permit efficient transferof time and other information.

BACKGROUND ART

With advanced television systems committee (ATSC) 3.0, one ofnext-generation terrestrial broadcasting standards, for example, it hasbeen determined that internet protocol (IP) packet including UDP/IP,i.e., user datagram protocol (UDP) packet, rather than transport stream(TS) packet will be used for data transmission. There are expectationsthat IP packet will be used in the future not only in ATSC3.0 but alsoin other broadcasting schemes.

It should be noted that when TS is broadcast, program clock reference(PCR) is transmitted as time information for synchronizing thetransmitting and receiving sides (refer, for example, to NPL 1).

CITATION LIST Non Patent Literature

[NPL 1]

“ARIB STD-B44 2.0 Edition,” Association of Radio Industries andBusinesses (general incorporated association)

SUMMARY Technical Problems

If time information is transmitted to synchronize the transmitting andreceiving sides in a broadcasting scheme such as ATSC3.0, efficienttransmission of that time information is required.

Efficient transmission of information as overhead other than timeinformation is also required.

The present technology has been devised in light of such circumstances,and an object of the present technology is to permit efficienttransmission of time and other information.

Solution to Problems

A first transmission device of the present technology is a transmissiondevice that includes a generation section and a transmission section.The generation section generates a physical layer frame having preamblesand a payload that includes, in the preamble, time informationrepresenting time of a given position in a stream of physical layerframes. The transmission section sends the physical layer frame.

A first transmission method of the present technology is a transmissionmethod that includes generation and transmission of a physical layerframe. The physical layer frame has preambles and a payload andincludes, in the preamble, time information representing time of a givenposition in a stream of physical layer frames.

In the first transmission device and the first transmission method ofthe present technology, a physical layer frame having preambles and apayload is generated and transmitted. The physical layer frame includes,in the preamble, time information representing time of a given positionin a stream of physical layer frames.

A first reception device of the present technology is a reception devicethat includes a reception section and a processing section. Thereception section receives a physical layer frame having preambles and apayload that includes, in the preamble, time information representingtime of a given position in a stream of the physical layer frames. Theprocessing section performs processes using the time informationincluded in the preamble of the physical layer frame.

A first reception method of the present technology is a reception methodthat includes reception of a physical layer frame and performance ofprocesses. The physical layer frame has preambles and a payload andincludes, in the preamble, time information representing time of a givenposition in a stream of the physical layer frames. Processes areperformed using the time information included in the preamble of thephysical layer frame.

In the first reception device and the first reception method of thepresent technology, a physical layer frame having preambles and apayload is received that includes, in the preamble, time informationrepresenting time of a given position in a stream of the physical layerframe, and processes are performed using the time information includedin the preamble of the physical layer frame.

A second transmission device of the present technology is a transmissiondevice that includes a generation section and a transmission section.The generation section generates a BB (BaseBand) frame that includes, ina BB header, order information on BB frame order. The transmissionsection sends the BB frame.

A second transmission method of the present technology is a transmissionmethod that includes generation of a BB (BaseBand) frame andtransmission of the BB frame. The BB frame includes, in a BB header,order information on BB frame order.

In the second transmission device and the second transmission method ofthe present technology, a BB (BaseBand) frame is generated andtransmitted. The BB frame includes, in a BB header, order information onBB frame order.

A second reception device of the present technology is a receptiondevice that includes a reception section and a processing section. Thereception section receives a BB (BaseBand) frame that includes, in a BBheader, order information on BB frame order. The processing sectionperforms processes using the order information included in the BB headerof the BB frame.

A second reception method of the present technology is a receptionmethod that includes reception of a BB (BaseBand) frame and performanceof processes. The BB frame includes, in a BB header, order informationon BB frame order. Processes are performed using the order informationincluded in the BB header of the BB frame.

In the second reception device and the second reception method of thepresent technology, a BB (BaseBand) frame is received that includes, ina BB header, order information on BB frame order, and processes areperformed using the order information included in the BB header of theBB frame.

It should be noted that the transmission device and the reception devicemay be independent devices.

Alternatively, the transmission device and the reception device may beinternal blocks making up a single device.

Advantageous Effect of Invention

According to the present technology, it is possible to efficientlytransmit time and other information.

It should be noted that the effect described here is not restrictive andmay be any one of the effects described in the present disclosure.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram illustrating a configuration example of anembodiment of a transmission system to which the present technology isapplied.

FIG. 2 is a diagram illustrating an example of a protocol stack forbroadcasting handled by the transmission system.

FIG. 3 is a diagram describing time information.

FIG. 4 is a diagram illustrating a network time protocol (NTP) packetformat.

FIG. 5 is a diagram describing an example of a position where timeinformation is placed.

FIG. 6 is a diagram describing a first placement example in which timeinformation is placed at the start of a payload of a physical layerframe.

FIG. 7 is a diagram describing type information of a generic packet.

FIG. 8 is a diagram describing a second placement example in which timeinformation is placed at the start of the payload of the physical layerframe.

FIG. 9 is a diagram describing a third placement example in which timeinformation is placed at the start of the payload of the physical layerframe.

FIG. 10 is a diagram describing extension type information (EXT_TYPE).

FIG. 11 is a diagram describing order information.

FIG. 12 is a diagram describing extension type information (EXT_TYPE) iforder information may be included in a BB header of a BB frame.

FIG. 13 is a diagram describing a first example of order information.

FIG. 14 is a diagram describing a second example of order information.

FIG. 15 is a diagram describing an example of how 16-bit offset time isgenerated as the second example of order information.

FIG. 16 is a diagram describing a third example of order information.

FIG. 17 is a block diagram illustrating a configuration example of atransmission device 10.

FIG. 18 is a flowchart describing an example of a transmission processhandled by the transmission device 10.

FIG. 19 is a block diagram illustrating a configuration example of areception device 20.

FIG. 20 is a flowchart describing an example of a reception processhandled by the reception device 20.

FIG. 21 is a diagram illustrating a configuration of a T2 frame(T2frame), a physical layer frame of digital video broadcasting(DVB)-T.2.

FIG. 22 is a block diagram illustrating a configuration example of anembodiment of a computer to which the present technology is applied.

DESCRIPTION OF EMBODIMENTS

<Embodiment of the Transmission System to which the Present Technologyis Applied>

FIG. 1 is a block diagram illustrating a configuration example of anembodiment of a transmission system to which the present technology isapplied.

In FIG. 1, the transmission system includes a transmission device 10 anda reception device 20.

The transmission device 10 sends, for example, services such as programs(digital broadcasting and data transmission). That is, the transmissiondevice 10 sends (transmits) a stream of target data to be sent such asimage and sound data as components making up a service such as program(television broadcast program) as a digital broadcasting signal via atransmission channel 30.

The reception device 20 receives the digital broadcasting signal sentvia the transmission channel 30 from the transmission device 10,restores the signal to its original stream, and outputs the stream. Forexample, the reception device 20 outputs image and sound data ascomponents making up a service such as program.

It should be noted that the transmission system in FIG. 1 is applicableto data transmission compliant with ATSC standards, DVB, integratedservices digital broadcasting (ISDB), and so on and to other kinds ofdata transmission. On the other hand, terrestrial waves, satellitecircuits, cable television networks (wired networks), and so on can beused as the transmission channel 30.

<Protocol Stack>

FIG. 2 is a diagram illustrating an example of a protocol stack forbroadcasting handled by the transmission system shown in FIG. 1.

That is, FIG. 2 illustrates a structure of data (packets and frames)handled by the transmission system shown in FIG. 1.

Data in a first layer (physical layer) L1, a second layer (datalinklayer) L2, and a third layer (network layer) L3 of the open systemsinterconnection (OSI) reference model is handled by the transmissionsystem.

In FIG. 2, an IP packet (IP Packet) is data in the third layer L3, and ageneric packet (Generic Packet) is data in the second layer L2. A BBframe (Baseband Frame), an FEC frame (FEC Frame), and a physical layerframe (Physical Frame) are data in the first layer L1.

In the transmission system shown in FIG. 1, data broadcasting isconducted by using an IP packet.

An IP packet includes an IP header (IP Header) and data (Data). Image,sound, and other data is placed in the IP packet data.

In the transmission device 10, a generic packet is configured(generated) from an IP packet.

The generic packet includes a generic header (Generic Header) and apayload (Payload). One or a plurality of IP packets are placed in thepayload of the generic packet.

In the transmission device 10, a BB frame is configured from a genericpacket.

The BB frame includes a BB header (Baseband Frame Header) and a payload(Payload). One or a plurality of generic packets are placed in thepayload of the BB frame.

In the transmission device 10, an FEC frame is configured by scramblingone or a plurality of BB frames as necessary and adding a physical layererror correction parity (Parity) to the BB frames.

Further, in the transmission device 10, physical layer processes such asbit interleaving, mapping to signal points in the constellation, andinterleaving in a time direction and in a frequency direction areperformed on one or a plurality of FEC frames as necessary. Then, in thetransmission device 10, a physical layer frame is configured by adding apreamble to the FEC frames that have undergone the physical layerprocesses.

That is, the physical layer frame includes preambles (BS, Preamble) anda payload (Payload). An FEC frame is placed in the physical layer framepayload.

In FIG. 2, the physical layer frame has, for example, “BS (BootStrap)”and “Preamble” as preambles as does an ATSC3.0's ATSC frame.

Here, “BS” is also referred to as a first preamble BS, and “Preamble” isalso referred to as a second preamble Preamble.

The first preamble BS corresponds, for example, to a P1 symbol making upa DVB-T.2's T2 frame, and the second preamble Preamble corresponds, forexample, to a P2 symbol making up a T2 frame.

On the other hand, the payload of the physical layer frame corresponds,for example, to a data symbol making up a T2 frame.

The physical layer frame structure used in DVB-T2 and ATSC3.0 has alength of approximately 100 to 200 ms. As for the physical layer frame,a payload that follows preambles can be acquired after acquiring thepreambles.

That is, the reception device 20 receives a physical layer frame anddemodulates the preambles of that physical layer frame. Further, thereception device 20 processes the payload of the physical layer frameusing the preambles of the physical layer frame and restores the FECframe, the BB frame, the generic packet, and the IP packet in this orderfrom the physical layer frame.

It should be noted that processing the payload of the physical layerframe requires preambles of that physical layer frame. Therefore, ifreception begins from halfway through the physical layer frame in thereception device 20, data received until the emergence of a nextpreamble after the start of reception is discarded.

<Time Information>

FIG. 3 is a diagram describing time information.

In the transmission system shown in FIG. 1, a physical layer frame isconfigured from an IP packet in the transmission device 10, and a streamof the physical layer frames is sent to the reception device 20 asdescribed in FIG. 2.

In an IP packet, time information like TS's PCR is not transmitted. Inorder to synchronize the transmission device 10 and the reception device20, it is preferred that time information be included in a stream ofphysical layer frames.

For this reason, the transmission device 10 can include time informationin a stream of physical layer frames.

Time information can be included in a preamble of a physical layer frameas illustrated in FIG. 3.

Here, approximately 30 to 40 bits are, for example, assumed in ATSC3.0as the first preamble BS of the preambles of the physical layer frame.Therefore, the first preamble BS may not have a sufficient bit length toinclude time information.

For this reason, time information can be included in the second preamblePreamble of the preambles of the physical layer frame.

Time information represents absolute time of a given position in astream of physical layer frames. Time of a given position in a stream isthe time of a given moment in the middle of processing of the bit at thegiven position by the transmission device 10. Among examples of the timeof a given moment in the middle of processing of the bit at the givenposition by the transmission device 10 are the time of the moment whenthe bit at the given position is output from a certain block of thetransmission device 10 and the time of the moment when the bit at thegiven position is processed by a certain block of the transmissiondevice 10.

Here, a given position in a stream of physical layer frames where timeinformation represents time will be referred to as a time position.

A starting position of the physical layer frame having a preambleincluding time information (starting position of the first preamble BS),for example, can be used as a time position.

Also, the boundary position of the physical layer frame having apreamble including time information between the first preamble BS andsecond preamble Preamble (ending position of the first preamble BS)(starting position of the second preamble Preamble), for example, can beused as a time position.

Further, the ending position of the second preamble Preamble of thephysical layer frame having a preamble including time information, forexample, can be used as a time position.

In addition to the above, an arbitrary position of the physical layerframe can be used as a time position.

It should be noted that sampling frequencies of the first preamble BSand the second preamble Preamble and beyond may be different in thephysical layer frame. If the sampling frequencies of the first preambleBS and the second preamble Preamble and beyond are different, time iscounted in different manners in the first preamble BS and the secondpreamble Preamble and beyond. Therefore, if the starting position of thefirst preamble BS is used as a time position, it may be necessary tochange the manner in which time is counted with respect to that timeposition during the first preamble BS and the second preamble Preambleand beyond. On the other hand, if the starting position of the secondpreamble Preamble is used as a time position, it is not necessary tochange the manner in which time is counted with respect to that timeposition, that is, the manner in which time is counted during the secondpreamble Preamble and beyond.

For this reason, the starting position of the second preamble Preambleof the physical layer frame having a preamble including time information(boundary position between the first preamble BS and the second preamblePreamble) is used as a time position in FIG. 3.

The preambles (first preamble BS and second preamble Preamble) arelocated at a fixed position of each physical layer frame, i.e., at thestart thereof, and the preambles are always processed first duringprocessing of the physical layer frame. Therefore, it is easy for thereception device 20 to acquire and process time information included ina preamble.

Also, preambles are transmitted comparatively robustly, making itpossible to transmit such preambles comparatively robustly.

Here, time information defined by NTP, time information defined by thirdgeneration partnership project (3GPP), time information defined byprecise time protocol (PTP), time information included in globalpositioning system (GPS), and arbitrary time information such as timeinformation in a uniquely determined format can be used as timeinformation.

FIG. 4 is a diagram illustrating an NTP packet format.

The 2-bit L1 is the abbreviation for Leap Indicator and indicates that aleap second will be inserted or deleted in the last minute of thecurrent month. The 3-bit VN is the abbreviation for Version Number andindicates an NTP version. The 3-bit Mode indicates an NTP operationmode.

The 8-bit Stratum indicates the level and is coded in accordance withthe level. The 8-bit Poll indicates the maximum interval betweenconsecutive NTP messages (in seconds) as a polling interval. The 8-bitPrecision indicates the system clock precision (in seconds).

Root Delay indicates, as a root delay, the round-trip delay untilreference time in NTP short format. Root Dispersion indicates the totaldelay dispersion until reference time in NTP short format. Reference IDindicates the identifier representing reference time. In a broadcastingsystem, “0000” indicating NULL can be stored.

Reference Timestamp indicates, as a reference timestamp, the time whensystem time was corrected last in NTP long format. Origin Timestampindicates, as a start timestamp, the time when a request was sent from aclient to a server in NTP long format. “0” can be stored in abroadcasting system.

Receive Timestamp indicates, as a reception timestamp, the server timewhen a request was received from a client in NTP long format. “0” can bestored in a broadcasting system. Transmit Timestamp indicates, as atransmission timestamp, the server time when a response was sent to aclient in NTP long format.

In addition to the above, an NTP packet has Extension Field 1 and Field2, extension fields, and moreover has, as necessary, Key Identifier anddgst (message digest).

As time information, 64-bit time information represented in the sameformat as timestamps such as NTP packet's Reference Timestamp can beused.

Here, there is a problem of time discontinuity caused by leap secondwith 64-bit time of NTP packet's timestamp. However, 64-bit time hassufficient granularity as time information included in the physicallayer frame.

Also, in addition to NTP packet's timestamp, time information defined by3GPP, i.e., timeInfo-r11 that is time information defined, for example,by 3GPP TS 36 331, can be used as time information.

timeInfo-r11 is 56 bits and includes 39-bit timeInfoUTC-r11, 2-bitdayLightSavingTime-r11, 8-bit leapSeconds-r11, and 7-bitlocalTimeOffset-r11. Although timeInfo-r11 lacks granularity to someextent as time information included in the physical layer frame, no leapsecond problem occurs.

In addition, 80 bits representing time defined by Institute ofElectrical and Electronics Engineers (IEEE)1588 can be used as timeinformation for time information defined by PTP, i.e., PTP packet. 48bits of the 80 bits representing time of a PTP packet represent time inseconds, and the remaining 32 bits represent time in nanoseconds.Therefore, time information defined by PTP has sufficient granularity astime information included in the physical layer frame and can representprecise time. Time information preferably represents time with moreprecision from the viewpoint of reproducing precise time in thereception device 10, and if time information defined by PTP is used astime information included in the physical layer frame, it is possible totransmit precise time information and reproduce precise time in thereception device 10. Further, no leap second problem occurs with timeinformation defined by PTP.

<Placement Position of Time Information>

FIG. 5 is a diagram describing an example of a position where timeinformation is placed.

Although, in FIG. 3, time information is placed (included) in thepreamble of the physical layer frame, time information may be placed,for example, in the payload of the physical layer frame as well as inthe preamble of the physical layer frame.

In FIG. 5, time information is placed at the starting portion of thepayload of the physical layer frame.

If time information is placed at the starting portion of the payload ofthe physical layer frame, the reception device 20 can acquire timeinformation placed at the start of the payload after processing thepreambles of the physical layer frame (first preamble BS and secondpreamble Preamble).

<First Placement Example in Which Time Information Is Placed in thePayload>

FIG. 6 is a diagram describing a first placement example in which timeinformation is placed at the start of the payload of the physical layerframe.

In the first placement example, time information is placed in thepayload of the generic packet at the start of the BB frame that is atthe start of the payload of the physical layer frame as the start of thepayload of the physical layer frame.

FIG. 6 illustrates a configuration example of a generic packet.

In the generic packet shown in FIG. 6, 3-bit type information (Type) isset at the start of the generic header. In this type information,information on the type of data placed in the payload of the genericpacket is set.

If time information and other signaling information for signalingpurposes is placed in the payload of the generic packet, “100” is, forexample, set in the type information of the generic header. Also, thetype information in which “100” is set is followed by a 1-bit reservedarea (Res: Reserved) in the generic header, and a header mode (HM:Header Mode) is placed next.

If “0” is set as the header mode, 11-bit length information (Length(LSB)) is placed thereafter. This length information is set to be thelength of the generic packet's payload. On the other hand, if “1” is setas the header mode, 16-bit length information in total made up of 11-bitlength information (Length (LSB)) and 5-bit length information (Length(MSB)) is placed thereafter, and further a 3-bit reserved area (Res) isprovided.

If “0” is set as the header mode, the length information (Length (LSB))is 11 bits long, and a value in the range from 0 to 2047 (=2¹¹−1) bytescan be represented as a payload length of the generic packet. However,11-bit length information cannot represent a payload length beyond 2048bytes. For this reason, if data equal to or more than 2048 bytes isplaced in the payload, “1” is set as the header mode. In this case, onebyte is added as a generic header area, thus providing 16-bit lengthinformation. A payload length equal to or more than 2048 bytes can berepresented by this 16-bit length information.

In the generic packet, a payload is placed following the generic headerconfigured as described above. Here, “100” is set as generic header typeinformation. Therefore, signaling information including time informationis placed as a payload.

FIG. 7 is a diagram describing type information of the generic packetshown in FIG. 6.

If an IPv4 IP packet is placed in the payload of the generic packet,“000” is set as type information. Also, if a compressed IP packet isplaced in the payload, “001” is set as type information. Further, if amoving picture experts group (MPEG)2-TS scheme's TS packet is placed inthe payload, “010” is set as type information.

Also, if signaling information such as time information is placed in thepayload, “100” is set as type information. It should be noted that threevalues of type information, namely, “011,” “101,” and “110,” areundefined (Reserved) in FIG. 7. Also, if three values of undefined(Reserved) type information alone lead to insufficient extension of typeinformation, (the range of) type information can be further extended bysetting “111” as type information.

<Second Placement Example in Which Time Information Is Placed in thePayload>

FIG. 8 is a diagram describing a second placement example in which timeinformation is placed at the start of the payload of the physical layerframe.

In the second placement example, time information is placed in theheader of the generic packet at the start of the BB frame that is at thestart of the payload of the physical layer frame as the start of thepayload of the physical layer frame.

FIG. 8 illustrates a configuration example of a generic packet.

As described in FIG. 6, type information on the type of data placed inthe payload of the generic packet is set in 3-bit type information(Type) at the start of the generic header in the generic packet.

In the second placement example, “000,” “001,” or “010” is set as 3-bittype information in the generic header.

As described in FIG. 7, if “000” is set as type information, an IPv4 IPpacket is placed in the payload, and if “001” is set, a compressed IPpacket is placed in the payload. Also, if “010” is set as typeinformation, a TS packet is placed in the payload.

In the generic header, 1-bit packet setup information (PC: PacketConfiguration) is placed following type information in which “000,”“001,” or “010” is set. If “0” is set as packet setup information, thegeneric header assumes normal mode (Normal mode), and 11-bit lengthinformation (Length) or 16-bit length information and a 3-bit reservedarea (Res) are placed in accordance with the header mode (HM) placedfollowing the packet setup information. Then, an IPv4 IP, a compressedIP, or a TS packet is placed in the payload following the generic headerin accordance with the type information of the generic header.

On the other hand, if “1” is set as a packet setup information (PC), thegeneric header assumes signaling mode (Signaling mode), and lengthinformation (Length) is placed in accordance with the header mode (HM)placed following the packet setup information. That is, if “0” is set asthe header mode, 11-bit length information (Length (LSB)) is placedthereafter. Further, the generic header is extended, and signalinginformation (Signaling) including time information is placed followingthe length information.

Also, if “1” is set as packet setup information (PC), and when “1” isset as the header mode (HM), 16-bit length information and a 3-bitreserved area (Res) are placed following the header mode. Further, thegeneric header is extended, and signaling information (Signaling)including time information is placed following the reserved area (Res).

Information up to the above signaling information (Signaling) is ageneric header (extended header), and a payload is placed thereafter. AnIPv4, a compressed IP, or other packet is placed in the payload inaccordance with the generic header type information.

<Third Placement Example in which Time Information is Placed in thePayload>

FIG. 9 is a diagram describing a third placement example in which timeinformation is placed at the start of the payload of the physical layerframe.

In the third placement example, time information is placed in the BBheader of the BB frame at the start of the payload of the physical layerframe as the start of the payload of the physical layer frame.

FIG. 9 illustrates a configuration example of a BB frame.

In FIG. 9, the BB frame includes a BB header and a payload (Payload). Inaddition to a 1- or 2-byte header (Header), a 1- or 2-byte optionalfield (Optional Field), and an extension field (Extension Field) may beplaced in the BB header.

A 1-bit mode (MODE) is set at the start of the header (Header).

If “0” is set as the 1-bit mode (MODE), 7-bit pointer information(Pointer (LSB)) is placed. It should be noted that pointer informationis information intended to indicate the position of the generic packetplaced in the payload of the BB frame. For example, if data of thegeneric packet placed last in a certain BB frame is placed in such amanner as to spread onto the next BB frame, it is possible to setposition information of the generic packet placed at the start of thenext BB frame.

Also, if “1” is set as the mode (MODE), 7-bit pointer information(Pointer (LSB)), 6-bit pointer information (Pointer (MSB)), and a 2-bitoptional flag (OPTI: OPTIONAL) are placed. The optional flag isinformation intended to indicate whether the BB header is extended byplacing an optional field (Optional Field) and an extension field(Extension Field).

If the optional field and the extension field are not extended, “00” isset as the optional flag. Also, if only the optional field is extended,“01” or “10” is set as the optional flag. It should be noted that if“01” is set as the optional flag, one byte (eight bits) is padded in theoptional field. Also, if “10” is set as the optional flag, two bytes (16bits) are padded in the optional field.

Also, if the optional field and the extension field are extended, “11”is set as the optional flag. In this case, 3-bit extension typeinformation (TYPE(EXT_TYPE)) is set at the start of the optional field.Information on extension length information (EXT_Length(LSB)) and anextension field type (Extension type) placed following the extensiontype information is set in this extension type information.

In the third placement example, signaling information including timeinformation is placed in the extension field (extension header).

That is, in the third placement example, “11” is set as the optionalflag (OPTI), and the optional field and the extension field areextended. Further, “011” is set as extension type information(TYPE(EXT_TYPE)) of the optional field, and signaling informationincluding time information is placed in the extension field.

FIG. 10 is a diagram describing extension type information(TYPE(EXT_TYPE)) shown in FIG. 9.

Information on extension length information (EXT_Length(LSB)) and anextension field type (Extension type) that are placed following theextension type information is set in the extension type information.

That is, if extension length information is placed, and if only stuffingbytes (Stuffing Bytes) are placed, “000” is set as the extension typeinformation. Also, if ISSY (Input Stream Synchronizer) is placed in theextension field without placing any extension length information, “001”is set as the extension type information. Further, if extension lengthinformation is placed, and if stuffing bytes are placed in the extensionfield together with ISSY, “010” is set as the extension typeinformation.

Also, if extension length information is placed, and if signalinginformation including time information is placed in the extension field,“011” is set as the extension type information. In this case, whether toplace stuffing bytes is determined arbitrarily. It should be noted thatextension type information from “100” to “111” is undefined (Reserved)in FIG. 10.

As described above, time information can be placed at the start of thepayload of the physical layer frame.

<Order Information>

FIG. 11 is a diagram describing order information.

As for the transmission system shown in FIG. 1, it is preferred that thereception device 20 has an arrangement for processing BB frames inorder.

For this reason, the transmission device 10 can include orderinformation on BB frame order in BB frames.

Order information can be included in the BB header of the BB frame asillustrated in FIG. 11.

Here, we will assume below that time information is included, forexample, in a preamble (first preamble BS or second preamble Preamble)of a physical layer frame as described in FIG. 3.

FIG. 11 illustrates a configuration example of a BB frame.

In FIG. 11, the BB frame includes a BB header and a payload (Payload).

The BB header includes a 1- or 2-byte header (Base Header).

Further, in addition to the header (Base Header), a 1- or 2-byteoptional field (Optional Field) and an extension field (Extension Field)can be placed in the BB header.

A 1-bit mode (MODE) is set at the start of the header (Header).

If “0” is set as the 1-bit mode (MODE), 7-bit pointer information(Pointer (LSB)) is placed. As described in FIG. 9, pointer informationindicates the position of the generic packet placed in the payload ofthe BB frame.

If “1” is set as the mode (MODE), 13=7+6-bit pointer information(Pointer (LSB) and Pointer (MSB)) and a 2-bit optional flag (OPTI:OPTIONAL) are placed.

The 13-bit pointer information includes 7-bit pointer information(Pointer (LSB)) and 6-bit pointer information (Pointer (MSB)). The 7-bitpointer information (Pointer (LSB)) and the 6-bit pointer information(Pointer (MSB)) represent the lower bit and the higher bit of the 13-bitpointer information, respectively. The optional flag indicates whetherthe header is extended by placing the optional field (Optional Field)and the extension field (Extension Field) as described in FIG. 9.

If the optional field and the extension field are not extended, “00” isset as the optional flag. Also, if only the optional field is extended,“01” or “10” is set as the optional flag.

3-bit extension type information (EXT_TYPE) on the extension field(Extension Field) is set at the start of the optional field.

If the optional flag is “01” or “10,” the extension type information isset to “000.” Further, 5-bit “00000” is set after the 3-bit extensiontype information “000” of the optional field.

If the optional flag is “10,” 8-bit “00000000” is set following 3-bitextension type information “000” and 5-bit “00000.”

If the optional flag is “11,” extension type information is set inaccordance with the extension field type (type of Extension field), and5-bit EXT_Length(LSB) or that 5-bit EXT_Length(LSB) and 8-bitEXT_Length(MSB) are set following the extension type information.

EXT_Length(LSB) represents, for example, lower six bits of informationon the extension field size, and EXT_Length(MSB) represents, forexample, higher eight bits of information on the extension field size.

It should be noted that EXT_Length(MSB) does not exist if a given valueis set as the extension type information (EXT_TYPE). If EXT_Length(MSB)exists, the extension field size is represented by 13 bits, the lowerbits of which are 5-bit EXT_Length(LSB) and the higher bits of which are8-bit EXT_Length(MSB). Also, if EXT_Length(MSB) does not exist, theextension field size is represented only by 5-bit EXT_Length(LSB).

If the optional field and the extension field are extended, “11” is setas the optional flag.

Then, order information is placed in the extension field (extensionheader) in accordance with the extension type information (EXT_TYPE).

That is, if order information is included in the BB header of the BBframe, the optional field and the extension field are extended bysetting “11” as the optional flag (OPTI). Further, order information isplaced in the extension field by setting, for example, “001” asextension type information (EXT_TYPE) of the optional field.

FIG. 12 is a diagram describing extension type information (EXT_TYPE)shown in FIG. 11 if order information may be included in a BB header ofa BB frame.

In FIG. 12, if extension type information is “000,” stuffing bytes(Stuffing Bytes), for example, are placed in the extension field(Extension Field).

Also, if extension type information is “001,” order information, forexample, is placed in the extension field (Extension Field).

In FIG. 12, extension type information having any other value isreserved (Reserved).

It should be noted that we assume that the generic packet placed in thepayload of the BB frame is placed in order and that the IP packet placedin the payload of the generic packet is placed in order.

In this case, when the BB frame order is maintained by orderinformation, the order of the generic packet placed in the payload ofthe BB frame is also maintained, and the order of the IP packet placedin the payload of the generic packet is also maintained.

<First Example of Order Information>

FIG. 13 is a diagram describing a first example of order information.

A clock count value obtained by counting a given clock, for example, canbe used as order information.

Here, ISSY is defined in DVB-T2, -C2, and -S2.

One of the elements making up ISSY is input stream clock reference(ISCR) that serves as a timestamp.

ISSY is two or three bytes in size, and ISCR is one of two types, shortor long.

Short ISCR is 15 bits in size, and 15-bit short ISCR makes up 2-byte(16-bit) ISSY together with 1-bit identification information foridentifying ISCR as a short ISCR.

Long ISCR is 22 bits in size, and 22-bit long ISCR makes up 3-byte(24-bit) ISSY together with 2-bit identification information foridentifying ISCR as a long ISCR.

ISCR is a count value obtained by counting a sampling clock, and a clockcount value, information similar to such ISCR, can be used as orderinformation.

In FIG. 13, a system clock of the transmission device 10 is counted by acounter in the transmission device 10, and a 24-bit count value, forexample, obtained by counting that system clock is output.

As order information to be included in a BB header of a frame, a clockcount value output from the counter when the BB frame is configured, forexample, can be used.

If a clock count value is used as order information, it is possible tomaintain order between BB frames (and by extension between genericpackets, and further between IP packets) by using a clock count value asorder information in the reception device 20. Further, it is possible toadjust (maintain) time between BB frames in the reception device 20.

It should be noted that if, for example, a 24-bit clock count value isused as described above, and if the clock counted by the counter is, forexample, a 6.144 MHz clock similar to ATSC3.0 sampling clock, it ispossible to count 1/(6.144 MHz)×2²⁴=2.73 seconds by using the 24-bitclock count value.

Also, if, for example, a 16-bit clock count value is used as orderinformation, and assuming, for example, that the clock counted by thecounter is a 6.144 MHz clock as described above, it is possible to count1/(6.144 MHz)×2¹⁶=10.6 milliseconds by using the 16-bit clock countvalue.

If a clock count value obtained by counting a 6.144 MHz clock is used asorder information, it is preferred, in consideration of the length ofthe physical layer frame, that the clock count value be 24 bits (threebytes) rather than 16 bits.

<Second Example of Order Information>

FIG. 14 is a diagram describing a second example of order information.

Offset time representing relative time of a BB frame position withrespect to time of a given position in a stream of physical layer framesincluding BB frames, for example, can be used as order information.

For example, time position where time information included in thepreamble of the physical layer frame represents time, i.e., for example,the starting position of the second preamble Preamble, can be used as agiven position.

In this case, offset time as order information included in a BB headerof a BB frame is time of the BB frame position with respect to timerepresented by time information included in the preamble of the physicallayer frame including that BB frame.

In FIG. 14, the time position of the first BB frame (BBF) of the payloadof a physical layer frame with respect to the time of the time positionrepresented by time information included in the preamble of thatphysical layer frame is 50.5 milliseconds.

Also, in FIG. 14, the time position of the second BB frame (BBF) of thepayload of a physical layer frame with respect to the time of the timeposition represented by time information included in the preamble ofthat physical layer frame is 73.79 milliseconds.

Assuming, here, that the unit time of the offset time as orderinformation is, for example, 10 microseconds, it is possible torepresent 0.65536 seconds (approximately 655 milliseconds)=10μseconds×2¹⁶ of time by using, for example, 16-bit (2-byte) offset time.

0.65536 seconds are, for example, a period of time equal to or longerthan the maximum length of ATSC3.0 physical layer frame and so on.Therefore, it is possible to represent the time of each BB frame withrespect to the time of the time position represented by time informationincluded in the preamble of that physical layer frame by using 16-bitoffset time as order information.

FIG. 15 is a diagram describing an example of how 16-bit offset time isgenerated as the second example of order information.

In FIG. 15, for example, a calculation section of the transmissionsection 10 calculates, as 16-bit offset time, the time position, i.e.,the difference between the time of the starting position of the secondpreamble of the physical layer frame and the time of the startingposition of the BB frame (BBF) included in that physical layer frame.

If offset time is used as order information, it is possible to maintainorder and time between BB frames in the reception device 20 by using aclock count value as order information as when a clock count value isused.

<Third Example of Order Information>

FIG. 16 is a diagram describing a third example of order information.

A frame count value obtained by counting a BB frame, for example, can beused as order information.

In FIG. 16, for example, a BB frame configured by the transmissiondevice 10 is counted by a counter in the transmission device 10, and an8-bit frame count value, for example, obtained by counting that BB frameis output.

A frame count value output from the counter, for example, when a BBframe is configured can be used as order information to be included inthe BB header of that frame.

If a frame count value is used as order information, it is possible tomaintain order between BB frames in the reception device 20 by using aframe count value as order information as when a clock count value oroffset time is used. It should be noted, however, that if a frame countvalue is used as order information, it becomes difficult to maintaintime between BB frames in the reception device 20.

It should be noted that if a frame count value is used as orderinformation, it is sufficient for the frame count value to be able tocount, for each physical layer frame, up to the maximum number of BBframes included in the physical layer frame in order to maintain theorder of BB frames.

Therefore, eight bits (one byte), for example, can be used as a size ofa frame count value.

Here, if, for example, 24 bits, 16 bits, and eight bits are used assizes of a clock count value, offset time, and a frame count value,respectively, as in the present embodiment, the 8-bit frame count valueis most advantageous in terms of low BB frame overhead.

<Configuration Example of the Transmission Device 10>

FIG. 17 is a block diagram illustrating a configuration example of thetransmission device 10 shown in FIG. 1.

In FIG. 17, the transmission device 10 includes an order informationacquisition section 61, a time information acquisition section 62, apreamble generation section 63, a component acquisition section 64, anencoder 65, a frame generation section 66, a transmission section 67,and an antenna 68.

The order information acquisition section 61 acquires (generates) orderinformation and supplies the order information to the frame generationsection 66.

The time information acquisition section 62 acquires time informationand supplies the time information to the preamble generation section 63.The acquisition of time information is conducted as follows. That is,when packets required to configure a BB frame arrive at a scheduler thatis not shown, a physical layer frame configured to include that BB frameis found from time t when the BB frame is generated by the framegeneration section 66, and time T at the start of the second preamblePreamble of that physical layer frame is found. Then, the time T issupplied to the time information acquisition section 62 from thescheduler as a control signal. Time information is included in thesecond preamble Preamble by the preamble generation section 63 whichwill be described later. It should be noted that time information can beused for signal frequency network (SFN) synchronization.

The preamble generation section 63 generates preambles (first preambleBS and second preamble Preamble) with time information from the timeinformation acquisition section 62 included, for example, in the secondpreamble Preamble and supplies the preambles to the frame generationsection 66.

The component acquisition section 64 acquires image and sound data ascomponents making up a service (e.g., program) and supplies the data tothe encoder 65.

That is, for example, the component acquisition section 64 acquiresappropriate content to suit the broadcasting time zone from a storagelocation of content already recorded or acquires live content from astudio or a filming location and supplies that content (its data) to theencoder 65.

The encoder 65 encodes the image and sound data supplied from thecomponent acquisition section 64 in accordance with a given encodingscheme and supplies the data to the frame generation section 66, forexample, in the form of IP packets.

The frame generation section 66 generates (configures) a physical layerframe by using, as appropriate, order information from the orderinformation acquisition section 61, preambles from the preamblegeneration section 63, and IP packets from the encoder 65 and suppliesthe physical layer frame to the transmission section 67.

That is, the frame generation section 66 configures generic packets inwhich IP packets from the encoder 65 are placed. Further, the framegeneration section 66 places the generic packets in the payload of a BBframe and configures the BB frame that includes order information fromthe order information acquisition section 61 in the BB header.

Also, the frame generation section 66 configures an FEC frame from theBB frame, subjects the BB frame to required processes, and places theFEC frame in the payload of a physical layer frame.

Then, the frame generation section 66 configures the physical layerframe by adding the preambles from the preamble generation section 63 tothe payload of the physical layer frame and supplies the physical layerframe to the transmission section 67.

The transmission section 67 performs digital modulation, upconversion,and other processes on the physical layer frame from the framegeneration section 66 and sends the frame as a digital broadcastingsignal via the antenna 68.

It should be noted that, in the transmission device 10 shown in FIG. 17,all functional blocks need not be placed in a single device and that atleast some of the functional blocks may be configured as a devicephysically independent from other functional blocks.

<Transmission Process>

FIG. 18 is a flowchart describing an example of a transmission processhandled by the transmission device 10 shown in FIG. 17.

In step S11, the time information acquisition section 62 acquires timeinformation and supplies the time information to the preamble generationsection 63, after which the process proceeds to step S12.

In step S12, the preamble generation section 63 generates preambles ofthe physical layer frame with time information from the time informationacquisition section 62 included in the second preamble Preamble andsupplies the preambles to the frame generation section 66, after whichthe process proceeds to step S13.

In step S13, the order information acquisition section 61 acquires orderinformation and supplies the order information to the frame generationsection 66, after which the process proceeds to step S14.

In step S14, the component acquisition section 64 acquires image andsound data as components making up a service and supplies the data tothe encoder 65.

The encoder 65 performs encoding and other processes on the image andsound data supplied from the component acquisition section 64 andsupplies the data to the frame generation section 66 in the form of IPpackets, after which the process proceeds from step S14 to step S15.

In step S15, the frame generation section 66 generates a physical layerframe by using, as appropriate, order information from the orderinformation acquisition section 61, preambles from the preamblegeneration section 63, and IP packets from the encoder 65 and suppliesthe physical layer frame to the transmission section 67, after which theprocess proceeds to step S16.

In step S16, the transmission section 67 sends the physical layer framefrom the frame generation section 66 as a digital broadcasting signalvia the antenna 68.

<Configuration Example of the Reception Device 20>

FIG. 19 is a block diagram illustrating a configuration example of thereception device 20 shown in FIG. 1.

In FIG. 19, the reception device 20 includes an antenna 71, a tuner 72,a demodulation section 73, a processing section 74, a display section75, and a speaker 76.

The antenna 71 receives a digital broadcasting signal from thetransmission device 10 and supplies the signal to the tuner 72.

The tuner 72 selects a given frequency channel component from thedigital broadcasting signal from the antenna 71, receives the physicallayer frame sent over that frequency channel, and supplies the physicallayer frame to the demodulation section 73.

The demodulation section 73 performs a demodulation process of thephysical layer frame supplied from the tuner 72.

That is, the demodulation section 73 demodulates the preambles (firstpreamble BS and second preamble Preamble) of the physical layer frameand further demodulates the payload of the physical layer frame byusing, as necessary, the demodulation result of the preambles.

Also, the demodulation section 73 demodulates (decodes) the FEC frameacquired by demodulation of the payload of the physical layer frame.

Then, the demodulation section 73 demodulates generic packets from theBB frame acquired as a result of demodulation of the FEC frame,demodulates IP packets from the generic packets, and supplies the IPpackets to the processing section 74.

Also, the demodulation section 73 acquires time information included inthe preamble of the physical layer frame and order information includedin the BB header of the BB frame during the demodulation process andsupplies the information to the processing section 74.

The processing section 74 decodes images and sounds of the program fromthe IP packets from the demodulation section 73 and supplies the imagesto the display section 75 and the sounds to the speaker 76.

Also, the processing section 74 (or the demodulation section 73)performs necessary processes using the time information and orderinformation from the demodulation section 73.

That is, the processing section 74 (or the demodulation section 73)performs, for example, a process of establishing synchronization withthe transmission device 10 using time information. Also, the processingsection 74 performs, for example, a process of maintaining order of theBB frame (order of the IP packets included in the payloads of thegeneric packets placed in the BB frame) and time thereof using orderinformation. It should be noted that time information can be used, forexample, to establish synchronization such as SFN synchronization forDVB-T.2 and for other purposes.

The display section 75 displays images from the processing section 74.The speaker 76 outputs sounds from the processing section 74.

It should be noted that although, in the reception device 20 shown inFIG. 19, a configuration in which the display section 75 and the speaker76 are built into the reception device 20 is described, the displaysection 75 and the speaker 76 may be provided externally.

<Reception Process>

FIG. 20 is a flowchart describing an example of a reception processhandled by the reception device 20 shown in FIG. 19.

In step S21, the tuner 72 receives a physical layer frame from a digitalbroadcasting signal from the antenna 71 and supplies the physical layerframe to the demodulation section 73, after which the process proceedsto step S22.

In step S22, the demodulation section 73 performs a demodulation processon the physical layer frame supplied from the tuner 72 and supplies IPpackets, time information, and order information obtained as a resultthereof to the processing section 74, after which the process proceedsto step S23.

In step S23, the processing section 74 performs a process ofestablishing synchronization with the transmission device 10 using timeinformation and further performs a process of maintaining order of theBB frame (order of the IP packets included in the payloads of thegeneric packets placed in the BB frame) using order information.

Then, with synchronization established with the transmission device 10and order of the BB frame maintained, the processing section 74 decodesimages and sounds of the program from the IP packets from thedemodulation section 73, supplies the images to the display section 75so that the images are displayed, and supplies the sounds to the speaker76 so that the sounds are output.

As described above, in the transmission system shown in FIG. 1, thetransmission device 10 includes time information in the preamble of thephysical layer frame and order information in the BB header of the BBframe for transmission, ensuring efficient transmission of timeinformation and order information.

Further, in the transmission system shown in FIG. 1, the receptiondevice 20 performs processes using time information included in thepreamble of the physical layer frame and order information included inthe BB header of the BB frame, allowing for speedy processing.

It should be noted that although, in the description given above, IPpackets are transmitted in the transmission system shown in FIG. 1, dataother than IP packets may be transmitted. That is, TS packets can betransmitted, for example, if a clock count value or offset time thatallows time adjustment between BB frames is used as order information.

Also, the transmission system shown in FIG. 1 is applicable for ATSC3.0,DVB, ISDB, and other arbitrary data transmission.

<DVB-T.2 Physical Layer Frame>

FIG. 21 is a diagram illustrating a configuration of a T2 frame(T2frame), a physical layer frame of DVB-T.2.

A T2 frame has P1 and P2 as preambles and a data symbol (Data Symbol) asa payload.

The P1 has P1 signaling, and the P2 has L1-pre signaling and L1-postsignaling.

The L1-post signaling has Configurable, Dynamic, Extension, CRC, and L1padding.

Time information can be included in the T2 frame preambles describedabove (e.g., P2 of the preambles).

Also, order information can be included in a BB header of a BB frameplaced as a data symbol of a T2 frame described above.

<Description of the Computer to which the Present Technology is Applied>

Next, a series of processes handled by the transmission device 10 andthe reception device 20 can be handled by both hardware and software. Ifthe series of processes are handled by software, the program making upthe software is installed to a computer.

FIG. 22 is a block diagram illustrating a configuration example of anembodiment of a computer to which the program handling the above seriesof processes is installed.

The program can be recorded, in advance, to a hard disk 105 as abuilt-in recording medium of the computer or to a read only memory (ROM)103.

Alternatively, the program can be stored (recorded) in a removablerecording medium 111. The removable recording medium 111 of this kindcan be provided as so-called packaged software. Here, among examples ofthe removable recording medium 111 are flexible disk, compact disc readonly memory (CD-ROM), magneto optical (MO) disk, digital versatile disc(DVD), magnetic disk, and semiconductor memory.

It should be noted that the program can be downloaded to the computervia a communication network or broadcasting network and installed to thehard disk 105 in addition to being installed to the computer from theabove removable recording medium 111. That is, the program can be, forexample, transferred from a download site to the computer in a wirelessmanner via an artificial satellite for digital satellite broadcasting orto the computer in a wired manner via a network such as local areanetwork (LAN) or the Internet.

The computer incorporates a central processing unit (CPU) 102, and aninput/output (I/O) interface 110 is connected to the CPU 102 via a bus101.

When an instruction is input by a user via the I/O interface 110 byoperating an input section 107, the CPU 102 executes the program, storedin the ROM 103, in accordance with the instruction. Alternatively, theCPU 102 loads the program stored in the hard disk 105 into a randomaccess memory (RAM) 104 and executes the program.

As a result, the CPU 102 performs the processes in accordance with theflowchart described above or the processes handled by the configurationin the block diagram described above. Then, the CPU 102 causes theprocessing result to be output from the output section 106 or sent froma communication section 108 via the I/O interface 110 and furtherrecords the processing result to the hard disk 105 as necessary.

It should be noted that the input section 107 includes a keyboard, amouse, a microphone, and so on. Also, the output section 106 includes aliquid crystal display (LCD), a speaker, and so on.

Here, in the present specification, the processes handled by thecomputer in accordance with the program need not necessarily beperformed chronologically according to the sequence given in theflowchart. That is, the processes handled by the computer in accordancewith the program include those performed in parallel or individually(e.g., parallel processes or object-based processes).

Also, the program may be processed by a single computer (processor) orby a plurality of computers in a distributed manner. Further, theprogram may be transferred to a remote computer and executed.

Further, in the present specification, the system refers to a set of aplurality of components (e.g., devices, modules (parts) or the like),and whether or not all the components are contained in the same housingdoes not matter. Therefore, a plurality of devices accommodated inseparate housings and connected via a network and a single device havinga plurality of modules accommodated in a single housing are bothsystems.

It should be noted that embodiments of the present technology are notlimited to that described above and can be modified in various wayswithout departing from the gist of the present technology.

For example, the present technology can have a cloud computingconfiguration in which one function is processed by a plurality ofdevices via a network in a shared and cooperative manner.

Also, each of the steps described in the above flowchart can beperformed not only by a single device but also by a plurality of devicesin a shared manner.

Further, if a plurality of processes are included in one step, theprocesses included in the one step can be performed not only by a singledevice but also by a plurality devices in a shared manner.

Also, the effect described in the present specification is merelyillustrative and not restrictive, and other effects are allowed.

It should be noted that the present technology can also have thefollowing configurations.

<1>

A transmission device includes a generation section adapted to generatea physical layer frame having preambles and a payload that includes, inthe preamble, time information representing time of a given position ina stream of physical layer frames, and a transmission section adapted tosend the physical layer frame.

<2>

The transmission device of feature <1>, in which the preambles have afirst preamble and a second preamble that follows the first preamble,and the time information is included in the second preamble andrepresents time of a starting position of the second preamble.

<3>

The transmission device of feature <1> or <2>, in which the timeinformation is time information defined by NTP, time information definedby 3GPP, or time information defined by PTP.

<4>

A transmission method includes generating a physical layer frame havingpreambles and a payload and includes, in the preamble, time informationrepresenting time of a given position in a stream of physical layerframes, and transmitting the physical layer frame.

<5>

A reception device includes a reception section adapted to receive aphysical layer frame having preambles and a payload that includes, inthe preamble, time information representing time of a given position ina stream of physical layer frames, and a processing section adapted toperform processes using the time information included in the preamble ofthe physical layer frame.

<6>

The reception device of feature <5>, in which the preambles have a firstpreamble and a second preamble that follows the first preamble, and thetime information is included in the second preamble and represents timeof a starting position of the second preamble.

<7>

The reception device of feature <5> or <6>, in which the timeinformation is time information defined by NTP, time information definedby 3GPP, or time information defined by PTP.

<8>

A reception method includes receiving a physical layer frame havingpreambles and a payload that includes, in the preamble, time informationrepresenting time of a given position in a stream of physical layerframes, and performing processes using the time information included inthe preamble of the physical layer frame.

<9>

A transmission device includes a generation section adapted to generatea BB (BaseBand) frame that includes, in a BB header, order informationon BB frame order, and a transmission section adapted to send the BBframe.

<10>

The transmission device of feature <9>, in which the order informationis a frame count value obtained by counting the BB frame.

<11>

The transmission device of feature <9>, in which the order informationis offset time representing relative time of a BB frame position withrespect to time of a given position in a stream of physical layer framesincluding the BB frames.

<12>

The transmission device of feature <9>, in which the order informationis a clock count value obtained by counting a given clock.

<13>

A transmission method includes generating a BB (BaseBand) frame thatincludes, in a BB header, order information on BB frame order, andtransmitting the BB frame.

<14>

A reception device includes a reception section adapted to receive a BB(BaseBand) frame that includes, in a BB header, order information on BBframe order, and a processing section adapted to perform processes usingthe order information included in the BB header of the BB frame.

<15>

The reception device of feature <14>, in which the order information isa frame count value obtained by counting the BB frame.

<16>

The reception device of feature <14>, in which the order information isoffset time representing relative time of a BB frame position withrespect to time of a given position in a stream of physical layer framesincluding the BB frames.

<17>

The reception device of feature <14>, in which the order information isa clock count value obtained by counting a given clock.

<18>

A reception method includes receiving a BB (BaseBand) frame thatincludes, in a BB header, order information on BB frame order, andperforming processes using the order information included in the BBheader of the BB frame.

REFERENCE SIGNS LIST

-   -   10 Transmission device, 20 Reception device, 30 Transmission        channel, 61 Order information acquisition section, 62 Time        information acquisition section, 63 Preamble generation section,        64 Component acquisition section, 65 Encoder, 66 Frame        generation section, 67 Transmission section, 68, 71 Antenna, 72        Tuner, 73 Demodulation section, 74 Processing section, 75        Display section, 76 Speaker, 101 Bus, 102 CPU, 103 ROM, 104 RAM,        105 Hard disk, 106 Output section, 107 Input section, 108        Communication section, 109 Drive, 110 I/O interface, 111        Removable recording medium

The invention claimed is:
 1. A transmission device comprising: circuitryconfigured to: generate a physical layer frame including a bootstrap, apreamble following the bootstrap, and a payload following the preamble,the preamble including time information representing time of a startingposition of the bootstrap and the time information representing a timethe bootstrap was processed by the transmission device; and send thephysical layer frame.
 2. The transmission device of claim 1, wherein thetime information is time information defined by precise time protocol.3. A transmission method comprising: generating a physical layer frameincluding a bootstrap, a preamble following the bootstrap, and a payloadfollowing the preamble, the preamble including time informationrepresenting time of a starting position of the bootstrap and the timeinformation representing a time the bootstrap was processed by thetransmission device; and transmitting the physical layer frame.
 4. Areception device comprising: circuitry configured to: receive a physicallayer frame including a bootstrap, a preamble following the bootstrap,and a payload following the preamble, the preamble including timeinformation representing time of a starting position of the bootstrapand the time information representing a time the bootstrap was processedby a transmission device; and perform processes using the timeinformation included in the preamble of the physical layer frame.
 5. Thereception device of claim 4, wherein the time information is timeinformation defined by precise time protocol.
 6. A reception methodcomprising: receiving a physical layer frame including a bootstrap, apreamble following the bootstrap, and a payload following the preamble,the preamble including time information representing time of a startingposition of the bootstrap and the time information representing a timethe bootstrap was processed by a transmission device; and performingprocesses using the time information included in the preamble of thephysical layer frame.